Some students have difficulty with the concept of relative vs. Particularly that the geologic time scale was first conceived through an understanding of the relative age of fossils.For many years, the geologic time scale had no units of 'time' attached to it.Only with the discovery of radioactivity could geologists attach numerical ages to time periods.

Even when they are told that a number that large has 10 digits, they cannot comprehend anything that large (particularly that amount of time).

| Religion | Examples & Exercises There are 5 main concepts with which students struggle when thinking about Deep Time - the concept that Earth has a multi-billion year history: When we tell students that the Earth is 4.6 billion years old, that number may have no meaning to them.

It is even difficult for many geoscientists to really come to a true understanding of how long 4,600,000,000 years really is.

In fact, many geologists find that it is easier to think about numbers (ages) like millions of years relative to the total age of the Earth or the length of geologic time.

To understand the time since the Earth's inception, we need to put it into perspective that we can understand.

To do this we often use analogies for the length of time rather than the absolute value of that time.

Here are a few examples in which significant events in Earth history are plotted relative to some known (and easily comprehended) quantity or object: Clearly, there are numerous analogies out there for deep time, make sure you choose one to which your students can relate.

Or, let your students choose the one that makes the most sense to them.

Suppose I gave you a list of "Relative" events: With a few clues, could you reasonably put them in chronological order? There are certain conditions that must be true in order for a sequential event to occur (e.g., my grandmother must be born and know my grandfather before my mother can be born).

The same is true for geologic events - there is a well understood set of principles that govern the deposition of sediments that can help a geologist tell a story about the history of the rocks.

Despite the fact that you can put the above events into a relative chronological order, you have no idea how much time occurs between each of the events.